1. Technical Field
Embodiments of the present invention generally relate to an image forming apparatus, such as a copier, a printer, a facsimile machine, or a multifunction peripheral (i.e., a multifunction machine) having at least two of copying, printing, facsimile transmission, plotting, and scanning capabilities, and a method of switching a collected developer route in an image forming apparatus.
2. Description of the Related Art
At present, image forming apparatuses such as printers and facsimile machines to output electronic data and copiers to copy documents are widely used. There are image forming apparatuses that employ electrophotography.
Electrophotographic image forming apparatuses form an electrostatic latent image on an image bearer, such as a photoconductor drum, develop the latent image with developer such as toner into a toner image, and transfer the toner image on a sheet of recording media. When the toner image is transferred from the image bearer onto the sheet, a certain amount of toner remains on the image bearer. Accordingly, after image formation, such toner is removed by a cleaning device and collected in a waste-toner container. The collected toner may be still usable. Disposing the still usable toner is not desirable from the viewpoint of environment conservation and running cost. Additionally, replacement frequency of the waste-toner container increases, thus making the maintenance and management of the apparatus more complicated.
Therefore, reuse of developer collected from the image bearer has been proposed. Reuse of collected developer is preferable since the amount of images produced with an identical amount of developer increases and the amount of waste developer is reduced.
Typical developer used in electrophotographic image forming apparatuses, however, is degraded while being exposed to heat, humidity, and outside air. Developer is also degraded by friction with a developer conveying mechanism, such as a developer conveying screw. Therefore, developer supplied from an isolated developer bottle to the developing device is gradually degraded with time. The degradation progresses in proportional to increases in the amount of driving of the developer conveying mechanism.
Depending on the degree of degradation, image quality is affected. For example, images become smeary, or toner is partly absent in the images. Although reuse of developer can reduce environmental impact, running cost of the apparatus, replacement frequency of waste-toner containers, it makes difficult to guarantee image quality since degraded developer is reused.
Thus, there is trade-off between advantages of reuse of developer and image quality guarantee.
To balance the advantages of reused of developer and image quality preservation, handling of collected developer may be switched between reuse and disposal.